Updated: Sep 26, 2019
What are proteins?
Proteins are one of the macronutrients. They are nitrogenous compounds that are “strings” of amino acids. Amino Acids are the building blocks of you. They make up everything in your body. Muscle, hair, bones, DNA, enzymes, everything. Amino acids can be broken down into 2 categories. Essential amino acids – meaning you can’t produce them, they must be ingested for you to use them, and non-essential amino acids – these you can produce on your own, given the right building blocks.
Essential amino acids, are an amino acid that cannot be synthesized de novo (from scratch) by the organism, and thus must be supplied in its diet. The nine amino acids humans cannot synthesize are phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine. (Wikipedia)
Six other amino acids are considered conditionally essential in the human diet, meaning their synthesis can be limited under special pathophysiological conditions, such as prematurity in the infant or individuals in severe catabolic distress. These six are arginine, cysteine, glycine, glutamine, proline, and tyrosine.
Five amino acids are dispensable in humans, meaning they can be synthesized in the body. These five are alanine, aspartic acid, asparagine, glutamic acid and serine.
Where do we get protein from?
For complete protein sources, that is, sources that contain an adequate proportion of each of the nine essential amino acids necessary in the human diet. Examples of single-source complete proteins are red meat, poultry, fish, eggs, milk, cheese, yogurt, soybeans and quinoa.
Plant foods are considered incomplete proteins because they are low or lacking in one or more of the amino acids we need to build cells. Incomplete proteins f